Guitar construction

ABSTRACT

An acoustic guitar having a neck attached to a hollow body is provided with a compression strut which relieves the hollow body of forces produced by tension of the strings. The compression strut extends from the string anchor to the neck over the sound opening in the upper surface of the body. The compression strut also supports the string-contacting bridge which is attached to said upper body surface. An adjustable support is positioned in the clearance space between the compression strut and said upper body surface.

United States Patent [1 1 Smith 1 June 12, 1973 GUITAR CONSTRUCTION [76] Inventor: Walter E. Smith, P. O. Box A,

Payette, Idaho 83661 [22] Filed: Nov. 26, 1971 [21] Appl. N0.: 202,371

[52] US. Cl 84/291, 84/318, 84/319 [51] Int. Cl. Gl0d 3/00 [58] Field of Search 84/267, 291, 297,

[56] References Cited UNITED STATES PATENTS 2,113,446 4/1938 Gugino 84/293 653,521 7/1900 Montoya... 84/267 583,102 5/1897 Utt 84/318 1,692,207 11/l928 Hall 84/314 2,416,593 2/1947 Proll 84/297 2,468,374 4/1949 Nelson 84/267 X Primary ExaminerStephen J. Tomsky Assistant ExaminerLawrence R. Franklin Attorney-Charles G. Lyon, John B. Young, Richard Elgar Lyon et a1.

[57] ABSTRACT An acoustic guitar having a neck attached to a hollow body is provided with a compression strut which relieves the hollow body of forces produced by tension of the strings. The compression strut extends from the string anchor to the neck over the sound opening in the upper surface of the body. The compression strut also supports the string-contacting bridge which is attached to said upper body surface. An adjustable support is positioned in the clearance space between the compression strut and said upper body surface.

5 Claims, 6 Drawing Figures PATENIED M I 21975 Y5 INVENTOR Y 144 4766 6. SM/TH '4 s A TTOE/V V5 GUITAR CONSTRUCTION This invention relates to stringed musical instruments and is particularly directed to improvements in a guitar of the so-called Spanish type having a hollow body with acoustic properties. In a conventional guitar of this type, the tension load of the guitarstrings must be absorbed by the hollow body and particularly the upper surface thereof which contains the conventional sound opening. This requirement of structural strength to oppose the stringed tension forces is often incompatible with the design for producing optimum sound quality, particularly where more than six strings are employed. For example, in a l2 string guitar, the structural strength required to resist the combined tension forces of the 12 strings may be greater than the guitar body can provide, and undesirable warping or failure is the result.

A feature of the present invention is the provision of a structural member or compression strut which is positioned between the upper surface of the guitar body and the tensioned strings, which strut serves to relieve the guitar body of the forces generated by the tensioned strings. One end of the strut is positioned adjacent the string anchor, and the other end of the strut is connected to the neck of the guitar, so that the neck of the guitar is subjected to the compression forces imposed by the tensioned strings, but the guitar body is not. The compression strut has clearance for the major portion of its length with respect to the upper surface of the guitar body, to avoid dampening of-the sound. A string-contacting bridge is supported on the compression strut and is attached to the upper surface of the guitar body.

Other objects and advantages will appear hereinafter.

In the drawings:

FIG. 1 is a perspective view showing a p'referrede'mbodiment of this invention.

FIG. 2 is a side elevation partly broken away.

FIG. 3 is a transverse sectional view taken substantially on the lines 33 as shown in FIG. 2.

FIG. 4 is a fragmentary view showing the manner of attaching the tensioned strings to the string anchor.

FIG. 5 is a sectional detail taken substantially on the lines 5-5 as shown in FIG. 4.

FIG. 6 is a view similar to FIG. 3 but showing a modification.

Referring to the drawings, the guitar generally designated 10, shown in FIGS. 1-5, has an acoustic hollow body 11 of conventional shape and construction joined to a neck 12. The neck'is provided with a nut 13 and a plurality of string-tensioning devices 14. The upper wall 15 of the body 11 is provided with the usual sound opening 16. A metallic anchor 17 for strings overlies a portion of the wall 15 and is provided with a right-angle footpiece 18 fixed to an end wall 19 of the body 11. A plurality of tensioned strings 21 extend from the string anchor 17 over the surface 22 of the bridge 23, over the fret board 24 of the neck 12 and over the nut 13 to the string-tightening devices 14. In the form of the invention shown in FIGS. 1-5, the plane of the strings between the bridge 23 and the nut 13 is disposed at an angle with respect to the upper surfaceof the wall 15 of the body 11, and the fret board 24 is also inclined, parallel with the plane of the strings 12. This feature of inclined strings is described in detail in my prior U.S. Pat. Nos. 3,398,622, 3,398,623 and 3,426,638.

In accordance with the present invention, a compression strut 27 extends acrossthe upper wall 15 of the guitar body 11 and is anchored at one end 28 by screws 29 adjacent the foot piece 18 of the string anchor 17. The compression strut 27 is anchored at the other end 30 by means of screws 31 which connect it to the neck 12. The compression strut 27 is formed'of metal and it extends directly over the sound opening 16. The major portion of the length of the compression strut is offset to pi'ovide clearance space 32 between the upper surface of the wall 15 of the guitar body and the lower surface of the compression strut. The central portion of the compression strut is curved in an arc and only the end portions 28 and 30 are in contact with the wall 15.

From this description it will be understood that the tension load of the strings 21 is taken by the compression strut 27 from the string anchor 17 to the neck 12, and accordingly the load on the guitar body from the string tension is minimized.

The strings 21 each have a looped end which encircles a groove in a spool element 35. The tension holds the spool element in a recess 36 in the end portion 37 of the string anchor 17. Each string 21 extends through its respective slot 38 formed in the head of the string anchor 17. The other ends of the strings 21 are connected in a conventional fashion to the stringtightenin'g devices 14 at the extending end of the neck 12.

The bridge 23 is connected to the upper wall 15 of the guitar body by threaded fastenings 40, but the bridge 23 is supported by its central post 41 which rests on the upper surface of the compression strut 27. The shape of the parts is such that the bridge 23 may apply an upward force to the wall 15 of the guitar body;

A movable support block 43 is positioned in the clearance space 32 and is clamped between the lower arcuate surface of the compression strut 27 and the upper surface of the wall 15 of the guitar body. This support block 43 is positioned near the corresponding location of the bridge on a corresponding conventional Spanish-type guitar, and its position may be adjusted slightly to produce the best quality sound. The degree of movement required for this adjustment is small, and is accommodated by slight deflection of the wall 15.

ha modified form of my invention shown in FIG. 6, the bridge 23a has a surface 22a which is not inclined and which is parallel to the upper wall 15a of the guitar body. This form of bridge 23a is used when the strings 21 'liein a plane parallel to the wall 15a, as with conventional guitars. The bridge 23a is provided with two posts 410 which rest on the compression strut 27, but is-not secured to the wall 150. The bridge 23a may or may not rest on the wall 15a; if not, the movable support block 43a acts as the only sound bridge. In other respects the device of FIG. 6 is the same as that described in connection with FIGS. 1-5.

Having fully described my invention, it is to be understood that I am not to be limited to the details herein set forth but that my invention is of the full scope of the appended claims.

I claim:

1. In a guitar, the combination of: a structure including a hollow body and a neck projecting from the body, a string anchor on the body and a nut on the neck remote from the body, a plurality of strings tensioned over the nut between the neck and the string anchor, a compression strut extending between the string anchor and the neck to relieve the body of at least a portion of the load applied by the tensioned strings, and a bridge contacted by the tensioned strings and supported on the compression strut.

2. In a guitar, the combination of: a hollow acoustic body having an upper surface provided with a sound opening, a neck fixed to said body at one side of said opening and projecting from said body, the neck having string-tightening means and having a nut, a string anchor secured to said body at the other side of said opening, a plurality of strings tensioned from said string anchor and over said nut, a compression strut operatively interposed between said string anchor and said neck to relieve said body of at least a portion of the force produced by the tension of said strings, and a bridge con-, tacted by the tensioned strings and supported on the compression strut, said bridge contacting said upper surface of said body.

3. The combination set forth in claim 2 in which the bridge is secured to the upper surface of the body.

4. The combination set forth in claim 2 in which the compression strut is shaped to contact said upper surface of the body only at the end portions of the compression strut, with clearance space over said body surface between said end portions, and a movable support positioned in said clearance space and contacting said compression strut and the upper surface of said body.

5. In a guitar, the combination of: a hollow acoustic body havingan upper surface provided with a sound opening, a neck fixed to said body at one side of said opening and projecting from said body, the neck having string-tightening means and having a nut, a string anchor secured tosaid body at the other side of said opening, a plurality of strings tensioned over said nut between said string anchor and said string-tightening means, a compression strut operatively interposed between said string anchor and said neck to relieve said body of a major portion of the force produced by the tension of said strings, and compression strut being shaped to contact said upper surface of the body only near the endportions of the compression strut, and having clearance space oversaid body surface between its end portions, a bridge near the sound opening contacted by the tensioned strings and supported upon the compression strut and contacting said body surface,

and a support spaced from said bridge, said support being positioned in said clearance space and contacting said compression strut and the upper surface of the body. 

1. In a guitar, the combination of: a structure including a hollow body and a neck projecting from the body, a string anchor on the body and a nut on the neck remote from the body, a plurality of strings tensioned over the nut between the neck and the string anchor, a compression strut extending beTween the string anchor and the neck to relieve the body of at least a portion of the load applied by the tensioned strings, and a bridge contacted by the tensioned strings and supported on the compression strut.
 2. In a guitar, the combination of: a hollow acoustic body having an upper surface provided with a sound opening, a neck fixed to said body at one side of said opening and projecting from said body, the neck having string-tightening means and having a nut, a string anchor secured to said body at the other side of said opening, a plurality of strings tensioned from said string anchor and over said nut, a compression strut operatively interposed between said string anchor and said neck to relieve said body of at least a portion of the force produced by the tension of said strings, and a bridge contacted by the tensioned strings and supported on the compression strut, said bridge contacting said upper surface of said body.
 3. The combination set forth in claim 2 in which the bridge is secured to the upper surface of the body.
 4. The combination set forth in claim 2 in which the compression strut is shaped to contact said upper surface of the body only at the end portions of the compression strut, with clearance space over said body surface between said end portions, and a movable support positioned in said clearance space and contacting said compression strut and the upper surface of said body.
 5. In a guitar, the combination of: a hollow acoustic body having an upper surface provided with a sound opening, a neck fixed to said body at one side of said opening and projecting from said body, the neck having string-tightening means and having a nut, a string anchor secured to said body at the other side of said opening, a plurality of strings tensioned over said nut between said string anchor and said string-tightening means, a compression strut operatively interposed between said string anchor and said neck to relieve said body of a major portion of the force produced by the tension of said strings, and compression strut being shaped to contact said upper surface of the body only near the end portions of the compression strut, and having clearance space over said body surface between its end portions, a bridge near the sound opening contacted by the tensioned strings and supported upon the compression strut and contacting said body surface, and a support spaced from said bridge, said support being positioned in said clearance space and contacting said compression strut and the upper surface of the body. 